I have one brother, who is 6 years younger than me. We always played together. We never had the big fights and fallings-out that I hear a lot of siblings closer in age have (and sometimes repair, sometimes not), and I think the age difference did play a part -- lack of direct competition, for example. While I was a teen-ager, my brother apparently was seriously hero-worshipping me (I was never a very girly girl, it has to be said) -- I didn't realise this at the time, but I learned it from later reports. We were always quite close until I moved to a different country, and even today (20 years later), we get along like a house on fire when we do meet.

I would not worry about a hole in the family. I can't say much for your other worries (except wish you all the best and hope with you that they come to nothing), but this one, you can put to rest.

(And hey, focusing on Alex sounds just like the best avoidance strategy I've heard of yet!)